malaria an overview of life-cycle, morphology and clinical picture
TRANSCRIPT
Malaria An Overview
of
Life-cycle,
Morphology
and
Clinical Picture
Malaria Species
Five species of malaria infect humans:
– Plasmodium falciparum– Plasmodium vivax– Plasmodium ovale– Plasmodium malariae– Plasmodium knowlesi
Malaria –Endemic Countries
Malaria –Endemic Countries
Exo-erythrocytic (hepatic) cycle
Hypnozoites
Sporozoites
Salivary Gland
LIFE CYCLE OF MALARIALIFE CYCLE OF MALARIA
Gametocytes
Erythrocytic Cycle
Zygote
Oocyst
Stomach Wall
Pre-erythrocytic (hepatic) cycle
sporozoites
Plasmodium falciparum::
Plasmodium vivax,
Plasmodium ovale
Plasmodium malariae\:
Components of the Malaria Life CycleComponents of the Malaria Life Cycle
Mosquito Vector
Human Host
Sporogonic cycle
Infective Period
Mosquito bitesgametocytemic person
Mosquito bitesuninfected person
PrepatentPeriod
Incubation Period
Clinical Illness
Parasites visible
Recovery
Symptom onset
CLINICAL CLINICAL SIGNS & SIGNS &
SYMPTOMS SYMPTOMS OF OF
MALARIAMALARIAFever
ChillsSweating
Malarial Paroxysm
cold stage•feeling of intense cold •vigorous shivering •lasts 15-60 minutes
hot stage •intense heat •dry burning skin •throbbing headache •lasts 2-6 hours
sweating stage •profuse sweating •declining temperature •exhausted and weak → sleep •lasts 2-4 hours
Chronic Disease
Chronic Asymptomatic
Infection
PlacentalMalariaAnemia
InfectionDuring
Pregnancy
Developmental Disorders;
Transfusions;Death
LowBirth weight
IncreasedInfant
Mortality
Acute DiseaseAcute Disease
Non-severeAcute Febrile
disease
Non-severeAcute Febrile
disease
Severe malaria
e.g.CerebralMalaria
Severe malaria
e.g.CerebralMalaria
Death
CLINICAL PICTURECLINICAL PICTURE
Definition
Severe malaria is defined as symptomatic malaria in a patient with P. falciparum with one or more of the following complications:– Cerebral malaria (unrousable coma not attributable to other causes). – Generalised convulsions (> 2 episodes within 24 hours) – Severe normocytic anaemia (Ht<15% or Hb < 5 g/dl)– Hypoglycaemia (glood glucose < 2.2 mmol/l or 40 mg/dl )– Metabolic acidosis with respiratory distress (arterial pH < 7.35 or
bicarbonate < 15 mmol/l) – Fluid and electrolyte disturbances– Acute renal failure (urine <400 ml/24 h in adults; 12 ml/kg/24 h in
children) – Acute pulmonary oedema and adult respiratory distress
syndrome– Abnormal bleeding– Jaundice– Haemoglobinuria– Circulatory collapse, shock, septicaema (algid malaria)– Hyperparasitaemia (>10% in non-immune; >20% in semi-
immune)
Definition
Uncomplicated malaria is defined as:
Symptomatic infection with malaria parasitemia without signs of severity and/or evidence of vital organ dysfunction.
Complications of malaria :
Cerebral malaria
Complications of malaria :
Pulmonary oedema
Child with severe malaria anaemia and no other malaria complication
Complications of malaria :
anaemia
Child with severe malaria anaemia in conjunction with acidosis and respiratory
distress
Clinical Picture :
Haemoglobinuria associated with malaria (“blackwater fever”) is uncommon and malarial haemoglobinuria usually presents in adults as severe disease with anaemia and renal failure.
Malarial haemoglobinuria
The two methods common in use :
1: Light microscopy
2: Rapid diagnostic tests (RDTs).
Common methods for parasitological diagnosis of malaria
Microscopy is the gold standard for
diagnosis of malaria
Parasite density
Species diagnosis
Monitoring response to treatment
CCMOVBD Plasmodium falciparum CCMOVBD Plasmodium vivax
CCMOVBD Plasmodium malariae Malaria Tutorials, Wellcome Trust Plasmodium ovale
Laboratory diagnosis of malaria
Laboratory diagnosis of malaria
Rapid diagnostic tests detect malaria antigens
Plastic cassette format of RDT
Rapid diagnostic tests detect malaria antigens
Rapid diagnostic tests detect malaria antigens
ACTION OF ANTIMALARIAL DRUG IN THE DIFFERENT LIFE ACTION OF ANTIMALARIAL DRUG IN THE DIFFERENT LIFE STAGES OF THE MALARIA PARASITESTAGES OF THE MALARIA PARASITE
Wellcome Trust (Modified)
Tissue SchizontocidesTissue Schizontocides•PrimaquinePrimaquine•PyrimethaminePyrimethamine•TetracyclineTetracycline•ProguanilProguanil
Anti-relapse (P.vivax)•primaquine
Blood Schizontocides•Chloroquine•Sulfadoxine/Pyrimethamine•Quinine•Artemisinins
GametocyideGametocyidePrimaquinePrimaquine
SporontocidesSporontocides•PrimaquinePrimaquine•PyrimethaminePyrimethamine•ProguanilProguanil